A study is being conducted on detecting the line-of-sight direction of a person to obtain information regarding what the person is interested in or to automatically execute an operation related to the line-of-sight direction or a position at which the person is gazing. Hereinafter, a position at which a person is gazing is simply referred to as a “gaze position”, for the sake of convenience.
Related technologies are disclosed in Japanese Laid-open Patent Publication No. 2003-144388 and Japanese Laid-open Patent Publication No. 2012-24154.